Sunday, 18 March 2012

History Of the Byzantine Empire

Constantine, now in firm command of the entire Roman empire (the first man for a long while to be in that position), is planning another initiative as significant as his adoption of Christianity. Immediately after the defeat of Licinius he sets about rebuilding Byzantium as a Christian capital city - one in which pagan sacrifice, the central rite of imperial Rome until this time, is specifically forbidden.

The city is ready by AD 330 for a ceremony of inauguration. Byzantium acquires two new names - New Rome and Constantinople, the city of Constantine. The Roman empire, within eighteen years of Constantine's first victory, has a new religion, a new centre of gravity and a significant change of culture.

Greece has always been the main cultural influence on Rome, and Greek is the language of the inhabitants of Byzantium. With the founding of Constantinople, the older culture effectively absorbs its vigorous younger challenger. Even the name Constantinopolis is Greek (polis meaning city).

Yet Constantinople is also the new Rome, capital of the Roman empire. The Greeks of this city will long continue to describe themselves as Romans. For several centuries Constantinople represents both the end of the Roman empire and the beginning of the Byzantine empire. Meanwhile Rome gradually establishes a new identity - as the seat of the Christian pope.

Byzantium offers the Roman emperor a clear strategic advantage as a centre of operation, for it is much closer than Rome to the threatened regions of the empire.

The main problems in the past century have been defending the Balkans from invaders beyond the Danube and protecting the Middle East from the Persians. Byzantium, renewed now as Constantinople, sits firmly between these troubled regions.

Constantine and his city: from AD 330

The emperor wastes no time in building monuments to proclaim Byzantium a Christian city. The focal point is a structure called the milion or milestone, from which all distances in the empire are now to be measured. It consists of four triumphal arches supporting a dome.

Nearby is the first church built here by Constantine. In this Greek city it is dedicated not to a martyr but to a concept, Holy Peace - the church of St Eirene. Probably before the end of Constantine's life, work begins on its famous neighbour, complete by 360 and sacred this time to Holy Wisdom - St Sophia.

Falling ill in AD 337, Constantine is at last baptized - only a few days before his death. It has often been asked why he left this necessary act of Christian commitment so late. The answer is probably so as not to waste the magic of baptism, which washes away sins. An emperor can hardly live a blameless life, and there are many blots on Constantine's record - such as his unexplained execution of his eldest son and his second wife in 326.

A late baptism guarantees a clean record on the day of judgement.

Three sons of Constantine: AD 337-361

On the death of Constantine, in AD 337, the empire is divided between his sons Constantine II, Constantius II and Constans. Since the time of his father, Constantius, the family has had a streak of constancy in its choice of names.

The sons inherit the parts of the empire which they have already ruled, on behalf of their father, as Caesars. Constantius II, though not the eldest, has the lion's share - Greece, Constantinople and the entire eastern empire. His elder brother, Constantine II, has Spain, Gaul and Britain. The youngest, Constans, controls Italy and Spain.

Peace and wisdom, in honour of which churches are now rising in Constantinople, do not make the brothers any more loving than other imperial families. Large numbers of their male relations are butchered at the start of the reign, and Constantine II meets his death in Italy in 340 when marching against Constans. Ten years later Constans is murdered in Gaul by an army commander with an eye on the throne. From AD 350 Constantius II is the only legitimate emperor.

With difficulty he recovers control of the entire empire. But from the point of view of Christianity, on which he is as keen as his father, he makes one cardinal error. He gives command of the west to his cousin Julian.

Julian the Apostate: AD 337-361

Son of a half-brother of Constantine the Great, Julian escapes the massacre of male members of the family which follows Constantine's death - probably because he is only six at the time. In his early 20s he studies in Athens, which still retains its status as the centre of Greek learning and pagan philosophy. Brought up strictly as a Christian, Julian now becomes a devotee of Greek culture. He is himself a talented writer in Greek, and several of his works survive.

Little of this would be remembered today, but for the unexpected accident of his becoming emperor. Subsequent events, in the two brief years of the 'apostate' on the throne, have mesmerized Christian historians.

In AD 356, when Julian is twenty-five, the emperor Constantius II appoints him Caesar in command of the Roman armies in Gaul. To everyone's surprise the young intellectual proves a brilliant general, winning a succession of victories over powerful tribes along the Rhine border.

In 359, needing reinforcements against Persia, Constantius orders many of Julian's best legions to march east. Instead, the troops stationed near Paris mutiny and proclaim Julian emperor. He moves slowly eastwards with them to what would have been a rebellious confrontation. But in 361 Constantius, moving westwards to meet him, dies in Asia Minor. Julian is emperor
The revival of the pagan cult: AD 361-363

It is not known exactly when the new emperor, Julian, decides to reinstate the ancient gods of Rome and Greece . At first he behaves with religious tolerance - returning to their sees, for example, Catholic bishops who have been exiled by Constantius, a committed follower of Arius. But by 362 Julian is making a prominent display of the ritual sacrifices which he carries out personally at revived pagan temples.

When Christians protest, he removes their relics from ancient shrines, imposes special taxes on Christian priests and gives preference to pagans in the civil service.

Julian is repeating, in reverse, the actions of his uncle Constantine in favouring Christianity. He intends to put in place a network of pagan priests and officials throughout the empire of the kind established by the Christians. This view of tomorrow does not appeal to yesterday's elite.

To what extent the young emperor might have achieved his aim is one of history's interesting speculations. In Christian eyes God gives a swift and decisive answer when Julian is killed, in 363, in a skirmish against the Persians. A rumour, first heard a century later, offers wry satisfaction. It is said that in his dying words the apostate cedes victory to Christ: Vicisti, Galilaee (Thou hast conquered, Galilean).

The frontiers of empire: AD 364-378

The death of Julian in warfare with Persia leads indirectly to a rare spell of peace on that frontier. The army selects as emperor a member of the royal household, by the name of Jovian, who extracts the Roman legions from a dangerous situation by making major concessions. Large tracts of territory in Mesopotamia and Armenia, long disputed, are abandoned to Persia.

Jovian dies of natural causes less than a year after becoming emperor. His concessions are regarded as shameful in Constantinople, but it is another forty years before war with Persia resumes.

On the other permanently threatened frontiers of empire, the Danube and the Rhine, the situation is very different. The pressure of barbarian tribes, themselves suddenly under threat from the Huns, is at last about to break down the barriers and flood the western empire.

The catastrophe begins when the emperor Valens is defeated and killed by the Visigoths at Adrianople in 378. His successor, Theodosius - an emperor subsequently accorded the title 'the Great' - solves the problem in the short term by settling the Visigoths as federates within the empire, or allies. But the intrusion of Goths, Vandals and Huns will over the next century disturb and finally destroy the Roman empire in the west.
Christian emperor and Christian bishop: AD 379-390

Theodosius becomes the eastern emperor in AD 379 and rapidly settles the religious splits within the empire by declaring pagan worship and Christian heresies (such as Arianism) to be illegal. A law of 380 orders all citizens to subscribe to the Catholic doctrines agreed under the chairmanship of Constantine the Great at the Council of Nicaea in 325.

A close link between church and state, with the state giving the lead, becomes a characteristic of the eastern or Byzantine empire. But Theodosius discovers, in a famous clash, that western bishops have authoritarian ideas of their own.

The cleric who sets a high standard for the western church in its relationship to the secular powers is Ambrose, bishop of Milan. In AD 390, when Theodosius is in Milan, there is a riot in Greece by supporters of a popular charioteer. A city governor is killed, and Theodosius sends orders for a brutal reprisal.

The charioteer's fans are invited into a circus for a special performance. Then the gates are locked. More than 5000 are slaughtered by troops in a massacre lasting three hours.

When news of the atrocity reaches Milan, Ambrose refuses to give communion to the emperor unless he does public penance for the crime. Theodosius at first stays away from church. But eventually he appears, bare-headed and wearing sackcloth in place of his sumptuous imperial robes. He repeats the performance on several occasions before Ambrose relents, finally giving his emperor the sacrament on Christmas Day.

In the threat of excommunication the western church discovers a powerful weapon for dealing with wayward rulers

Rome and Constantinople: 4th - 5th century AD

The balance between Rome and Constantinople, and the potential for an upset, is becoming more clearly defined. Two imperial courts, east and west, have been a familiar part of the empire's history. In effect they are more like two army camps, permanently on the move. If they come too close to each other, the result has often been war.

With two rival cities, both interested in political and religious priority, the situation is more complex. In the mid-4th century, under Constantius II, the senate in Constantinople is given equal authority with that of Rome. A few years later, at the Council of Constantinople in 381, it is stated that the bishop of Constantinople is of equal status to the bishop of Rome.

On the religious front an uneasy truce is maintained for several centuries. The final schism between Rome and Constantinople, acknowledging the separate Roman Catholic and Greek Orthodox churches, becomes only gradually evident during the Middle Ages.

In the military sphere the pace is forced by events largely beyond the emperors' control. Theodosius rules the entire empire with considerable skill until 395, and his descendants remain at least nominally in control of both east and west until 455. But any measure of peace in the west has been bought by compromise with German tribes.

Odoacer, king of Italy: AD 476-493

German mercenaries by now form an important part of any Roman army, and Roman armies play a major role in the making and breaking of emperors. This is the case in a fairly normal putsch of AD 476, but it is followed by an unusual demand from the mercenaries. They want to settle in Italy. They suggest that a third of every landowner's estate should be made over to them.

The suggestion is not as unreasonable as it sounds. Roman soldiers have in the past been rewarded with land, and barbarian tribes have been settled in provinces of the empire as federates. But it is a shocking thought to Romans that this provincial system might apply to Italy itself. The mercenaries' demand is rejected.

There is an immediate mutiny. The tribesmen elect one of their number, Odoacer, as their king. He leads them to a rapid victory, but immediately makes it clear that his intention is not to destroy the western empire. He wants to be part of it. He sends ambassadors to the emperor Zeno in Constantinople, acknowledging the emperor's rule but asking to be allowed to govern Italy as king of his own people. Zeno reluctantly agrees, subject to certain points of protocol.

The senate in Rome accepts the fait accompli with better grace, for Odoacer proves an effective ruler within the traditional Roman system. He even finds land for his German tribesmen without causing undue upheaval.

The end of the Roman empire? AD 476

The acceptance of Odoacer as king of Italy in 476 causes this year to be seen as the end of the Roman empire. And in a real sense it is. Kings and popes, neither of them part of Roman imperial tradition, will henceforth wield power in the Italian peninsula.

But this is the perspective of hindsight. To historians Constantinople is by this time the capital of the young Byzantine empire. To Europeans in the 5th century it is still the centre of the very ancient Roman empire. In imperial terms there is nothing new about chaos and upheaval in the west, and Roman emperors in Constantinople will continue to take active steps to reassert their authority. In 488 this is done with the help of the Ostrogoths.
Theodoric the Ostrogoth: AD 487-526
The Ostrogoths have as yet intruded less than the Visigoths upon the imperial territories of Rome and Contantinople. In recent times, in their region north of the Black Sea, they have been subdued by the Huns. But after the collapse of the Huns, in the mid-5th century, the Ostrogoths press down across the Danube into the Balkans.

In 487, under the leadership of Theodoric, they almost succeed in capturing Constantinople. The Byzantine emperor, Zeno, finds a brilliant short-term solution to this immediate problem. Having recently had to relinquish Italy to one barbarian, Odoacer, he now invites Theodoric to invade Italy and take Odoacer's place.

Theodoric arrives in Italy in AD 489. In the twelve months from August 489 his Ostrogoths confront Odoacer in three separate battles. In each they are victorious, but they fail to dislodge Odoacer from his stronghold at Ravenna. This is eventually achieved by negotiation, with the bishop of Ravenna as the intermediary. It is agreed that Theodoric and Odoacer will rule Italy jointly. On 5 March 493 the gates of the city are opened to Theodoric.

Ten days later Theodoric invites Odoacer to a banquet. During it he kills his guest with his own hand, after which Odoacer's retinue is murdered.

Theodoric's long reign in Italy begins with this treachery, but the murder of Odoacer proves untypical of the Ostrogothic king. His thirty-three years on the throne bring a period of calm to turbulent Italy, justifiably earning him the title Theodoric the Great. He is the first barbarian king from the Germanic tribes of northern Europe to establish a settled and civilized rule - to which his buildings in Ravenna still bear witness. His achievements win him a lasting place in legend, as Dietrich von Bern.

Theodoric never deviates from his arrangement with Constantinople. He rules in Italy as the emperor's appointed military governor - becoming thereby an accepted part of the Roman empire rather than its enemy.

Theodoric has the good sense to leave the administration of Italy virtually unchanged and in the hands of Romans. They are prevented from serving as soldiers, but similarly Goths may not join the bureaucracy. The arrangement suits even the papacy. Though himself an Arian, Theodoric makes no attempt to interfere in Roman Catholic affairs. Indeed he is so much trusted that when there are two rival claimants to the papal see, in 498, he is invited to choose between them.

Nevertheless the rule of a barbarian Arian in Italy is unacceptable in the longer term. The inadequacy of Theodoric's immediate successors prompts the campaign of 535 by Justinian to recover Ravenna.

Justinian and Theodora: AD 527-548

The emperor who comes to the throne in AD 527 restores the western empire to much of its former glory, reforms the legal and administrative system of his realm, and commissions churches and mosaics which emphasize the imperial dignity of Christianity.

He also contracts a marriage which makes him and his bride the most famous couple in Byzantine history. He is Justinian. His wife, an ex-courtesan, is Theodora. They feature in mosaic, facing each other from opposite walls, in the church of San Vitale in Ravenna.

Justinian is born in AD 483 into a peasant family in the Balkans, near Skopje, but from his early years he receives a good education in Constantinople; his uncle has risen to high command in the army and becomes emperor in 518 as Justin I. Theodora is of much less respectable origins. Born the daughter of a bear-keeper in the circus at Constantinople, she makes her mark as a child actress and then as a courtesan in various cities of north Africa and Anatolia.

In Constantinople she attracts the attention of Justinian, nearly twenty years her senior. He persuades his uncle, now emperor, to revoke a law banning marriage between men of senatorial rank and actresses.

Justinian and Theodora are married in AD 525 in Constantine's church, the first Santa Sophia. Two years later Justinian's uncle dies and they become emperor and empress. Until her early death, in 548, Theodora plays an almost equal role with her husband in running the empire - not least in the resolve which she shows in persuading him to stay in Constantinople in the civil disorder which nearly ends his rule, the so-called Nika revolt of 532.

The rioters burn many of the most famous buildings of the capital city, including the church in which Justinian and Theodora were married. Together the couple supervise its replacement with one of the world's most spectacular buildings.

Santa Sophia: AD 537

In Santa Sophia in Constantinople (completed astonishingly in only five years) the architects working for Justinian achieve with triumphant skill a new and difficult feat of technology - that of placing a vast circular dome on top of a square formed of four arches.

The link between the curves of two arches (diverging from a shared supporting pillar) and the curve round the base of the dome is made by a complex triangular shape known as a pendentive (see Squinch and pendentive). Santa Sophia (or Hagia Sophia, the two being Latin and Greek for 'Holy Wisdom'), is not the first building in which a pendentive is used. But it is by far the most impressive.A code of law: AD 527-534
By the time of Justinian nearly 600 years have passed since the last years of the Roman republic, in the 1st century BC. Many laws from all these centuries are still in force, but they exist only in scattered and often rare manuscripts. Consistency is impossible.

Justinian begins his reign with an energetic programme of reform in the administration of the civil service, in the collection of tax and in the field of law. Tackling corruption in the bureaucracy and improving the tax revenue bring immediate unpopularity (seen in The Nika revolt of 532). But tidying up the Roman law is an achievement for which Justinian has won lasting fame.

On his accession Justinian inmediately appoints a ten-man commission to collate all the statutes of past administrations and thus provide a clear version of the constitution. They complete their task in fourteen months. The resulting Codex Constitutionum is published in AD 529.

In 530 Justinian sets a team of sixteen to the task of assembling the opinions of the jurists. This too is completed within three years and is published in 533 as Digesta. The result modifies to some extent the conclusions of the earlier Codex, which is issued in a revised form in 534.

The Codex of 534 is the Justinian code of law which has come down in history. It consists of twelve books containing 4652 laws and amendments, spanning the four centuries from Hadrian to Justinian himself.

This great legal effort, carried out on the emperor's behalf, is not legislation in the same sense as the Napoleonic code of civil law (which breaks new ground). It is more in the nature of academic clarification - of inestimable value in its own time to legal practitioners, and in subsequent ages to those who study Roman law.

Justinian's armies: AD 532-561

When Justinian comes to the throne, the empire is engaged as usual in the struggle in the east against Persia. A peace is agreed in AD 532 with a new Persian monarch, Khosrau I (who breaks it dramatically in his raid on Antioch in 540). Later a series of settlements culminate in a 50-year-truce signed in 561.

The eastern frontier is a distraction from the campaigns which more greatly inspire Justinian. He is determined to recover the Roman empire in the west from heretical barbarians. With the help of a brilliant general, Belisarius, he has considerable success - against the arian Vandals in north Africa, the Arian Ostrogoths in Italy and the Arian Visigoths in Spain.

Byzantine Africa: 6th - 7th century AD

The expansionist energy of Justinian in Constantinople, and of his great general Belisarius in the field, brings the whole of the North African coast back under Roman rule for one final century. In 533 Belisarius defeats the Vandals in battle, captures their king and enters Carthage unopposed.

The authority of the emperor is restored, though the northwest tip of the continent is never again brought fully under control (in spite of pioneering efforts by Belisarius in the building of castles). Carthage rejoins Alexandria as a great imperial city on this important coast, rich in grain. But in the next century they both fall, in turn, to an entirely unexpected new power - the Arabs.

The recovery of Byzantine Italy: AD 535-568

In AD 535 a fleet sails from Constantinople with orders to re-establish direct imperial rule in Italy. The campaign is under the command of Belisarius, hero of the recent African successes. He begins his task in the south, capturing Sicily in 535 and moving north to take Naples and Rome in the following year. Once again the fortified capital city, Ravenna, proves the hardest place to subdue. The Ostrogoths hold out against him here until 540.

When Ravenna finally falls in that year, the task seems complete. Belisarius returns to Constantinople. But Byzantine confidence is premature.

Within a few years the whole of Italy has been recaptured by the Ostrogoths, apart from three well guarded enclaves on the east coast (Ravenna, Ancona and Otranto). A long campaign by a eunuch general, Narses, eventually restores Byzantine control over the entire peninsula but this is not achieved until 562 - less than a decade before the arrival on the Italian scene of yet another Germanic tribe.

The Lombards, invading in 568, rapidly overrun the rich north Italian plain, from which the Byzantines never again shift them. Their arrival introduces the many centuries in which a united Italy will be nothing more than a dream, based on nostalgic memories of imperial Rome.
Exarchate of Ravenna: AD 584-751

In an attempt to hold the remaining Byzantine possessions in Italy against the Lombards, the emperor Maurice groups them from about AD 584 in a new administrative structure based in Ravenna. In command of the entire region is an exarch - a provincial governor with absolute power over both military and civilian affairs.

At first the exarch governs most of Italy south of the Po, together with the coastal strip round the north Adriatic - including the modest settlements on the islands of the Venetian lagoon, recently established by refugees from the advancing Lombards. Corsica and Sardinia come under another exarch, ruling from Carthage. Sicily becomes linked more directly with Constantinople.

This swathe of territory soon proves impossible to hold. During the 7th century the Lombards steadily extend their territory in the north, and local dukes take possession of much of the south of Italy. In the 8th century ancient cities such as Naples and papal Rome show increasing signs of independence. In 726 even upstart Venice begins to choose its own dukes, or doges.

By the middle of the 8th century the Lombards have seized much of the territory inland from Ravenna, and in 751 they take Ravenna itself. Byzantine influence on places such as Venice will remain strong. But Italy can no longer be said to be part of the old Roman empire.

Byzantium and Persia: 6th - 7th century AD

The final and most destructive chapter in the rivalry between the Byzantine empire and Persia begins in an improbable way. In AD 591 both emperors find themselves fighting on the same side.

Khosrau II has fled from Persia after the murder of his father. He enlists the support of the Byzantine emperor, Maurice, who marches east to restore Khosrau to his inheritance - in return for some useful territorial concessions in Armenia and Mesopotamia. The result is peace between the two sides until 602, when Maurice is murdered in a Byzantine upheaval. Khosrau, seeing his own opportunity, moves to avenge his friend's death. In the next few years the Persians devastate the Byzantine cities of the Middle East.

The first Christian city to fall to Khosrau's armies is Antioch, in 611. Damascus follows in 613. In the spring of 614 a Persian army enters Palestine and moves through the countryside, burning churches. Only the church built by St Helena in Bethlehem is spared; the Persians recognize themselves in the costumes of the Magi, seen bringing their gifts to the infant Jesus in a mosaic above the entrance.

The army reaches Jerusalem in April. The Patriarch urges the inhabitants to surrender, so as to avoid bloodshed, but they resist for a month. When the city falls, it is said that some 60,000 Christians are massacred and another 35,000 sold into slavery.

From the point of view of the Christian hierarchy, far away in Constantinople, the Persians commit one even greater affront. After sacking Jerusalem, they carry off to Ctesiphon the most holy relic of Christendom, the True Cross of Christ.

Its restoration to Jerusalem becomes an urgent matter of state.

Recovering the relic: AD 622-629

Under the emperor Heraclius, Byzantium has been quietly regaining its strength. In AD 622 Heraclius feels ready to take the field against the Persians. His successes are as rapid and spectacular as the reverses of the previous decade. By 624 he has swept through Asia Minor and Armenia to reach Azerbaijan, to the north of Persia between the Black Sea and the Caspian.

Here, as if avenging the violation of the True Cross, he destroys one of the most sacred fire temples of Zoroastrianism.

In the next few years the swings of fortune become even more extreme. In 626 a Persian army reaches the Bosphorus, but fails to cross the water to support a siege of Constantinople's massive walls by a barbarian horde of Slavs and Avars. In 627 a Byzantine army under Heraclius penetrates Mesopotamia far enough to defeat the Persians at Nineveh and destroy Khosrau's palace at Ctesiphon.

From a position of strength Heraclius negotiates the return of the True Cross. He takes it back to be displayed in Constantinople, and then personally returns it, in 629, to the Holy Sepulchre in Jerusalem. But the relic proves powerless against the next threat to Jerusalem in 638.

The Arab conquests: 7th century AD

One of the most dramatic and sudden movements of any people in history is the expansion, by conquest, of the Arabs in the 7th century (only the example of the Mongols in the 13th century can match it). The desert tribesmen of Arabia form the bulk of the Muslim armies. Their natural ferocity and love of warfare, together with the sense of moral rectitude provided by their new religion, form an irresistible combination.

When Muhammad dies in 632, the western half of Arabia is Muslim. Two years later the entire peninsula has been brought to the faith, and the Arab nomads are Muslim in the desert to the east of Palestine and Syria.
The Arabs continue rapidly westwards along the coast of North Africa, capturing Cyrenaica in 642 and Tripoli in 643. But these remain largely ineffective outposts. For nearly three decades the Arabs make little progress in subduing the indigenous Berber inhabitants of this coastal strip.

The turning point comes in 670 with the founding of a new Arab garrison town at Kairouan, about sixty miles south of the Byzantine city of Carthage. From this secure base military control becomes possible. Carthage is destroyed (yet again) in 698. By the early 8th century northwest Africa is firmly in Arab hands. In 711 an Arab general takes the next expansionist step. With a Berber army he crosses the straits of Gibraltar and enters Spain.The Arabs and Constantinople: AD 674-717

In the overwhelming assault on the Byzantine empire by the Arabs during the 7th century, only one campaign is consistently unsuccessful. This is their frequently repeated attempt to capture Constantinople itself.

The city is first unsuccessfully attacked, by sea and land, in AD 669. The last of several expeditions ends in disaster for the Arabs in 717, when a fleet of some 2000 ships is destroyed by a storm and the army straggles homewards through a wintry Anatolia. From the mid-670s the Byzantines have one strong psychological advantage - a mysterious new device in their armoury which becomes known as Greek fire.Greek fire: AD 674

In AD 674 a Muslim fleet enters the Bosphorus to attack Constantinople. It is greeted, and greatly deterred, by a new weapon which can be seen as the precursor of the modern flamethrower. It has never been discovered precisely how the Byzantine chemists achieve the jet of flame for their 'Greek fire'. The secret of such a lethal advantage is jealously guarded.

Contemporary accounts imply that the inflammable substance is petroleum-based, floats on water, and is almost impossible to extinguish. It can be lobbed in a canister. But in its most devastating form it is projected, as a stream of liquid fire, from a tube mounted in the prow of a ship. Sprayed among a wooden fleet, its destructive potential is obvious.Iconoclasm: AD 726-843

In AD 726 the Byzantine emperor Leo III issues a dramatic order. Above the bronze gates leading into his imperial palace there has been, since the time of Justinian, a vast golden image of Jesus Christ - the partner and the source of the authority of Byzantine emperors. Leo sends a body of troops to destroy this great icon (from eikon, Greek for 'image').

Local outrage is so great that the crowd kills the officer in charge. The event begins a century and more of the so-called Iconoclastic Controversy, which racks the empire and contributes considerably to the developing split between Rome and Constantinople.

Leo has the support of many in the eastern provinces of the empire, and he has strong arguments on his side. Icons are greatly venerated within the Byzantine church, in unmistakable disregard of God's second Commandment (prohibiting 'graven images'). Islam, taking the same prohibition with the utmost seriousness, has been for almost a century a neighbouring source of rebuke. A majority of Christian leaders in the east (the region most affected by Islam) support Leo's policy.

Undeterred by widespread popular unrest following the first iconoclastic act of 726, Leo goes further down his chosen route. In 730 he declares the possession of icons to be illegal, and orders their destruction.

The battle between the iconoclasts (klastes, Greek for 'breaker') and the iconodules (doulos, 'servant' and thus 'worshipper') is a political one with violent consequences for early Byzantine art. But Pope Gregory III in Rome will have none of it, and Roman Catholics have always remained passionate iconodules.

In the eastern empire there is an interlude from AD 787, when iconodules win power, but iconoclasm is restored as imperial policy in 814. The controversy lasts until 843. In that year Theodora, the widow of the emperor Theophilus, officially sanctions the veneration of icons - an event still celebrated each year in the eastern church as the Feast of Orthodoxy.

The great Christian cities of Syria and Palestine fall to the Arabs in rapid succession from AD 635. Damascus, in that year, is the first to be captured. Antioch follows in 636. And 638 brings the greatest prize of all, in Muslim terms, when Jerusalem is taken after a year's siege.

It is a moment of profound significance for the young religion, for Islam sees itself as the successor of Judaism and Christianity. The city of the people of Moses, in which Jesus also preaches and dies, is a holy place for Muslims too. Moses and Jesus are Muhammad's predecessors as prophets. A link with Muhammad himself will also soon emerge in Jerusalem.

Muslim North Africa: from AD 642

The Arab conquest of Egypt and North Africa begins with the arrival of an army in AD 640 in front of the Byzantine fortified town of Babylon (in the area which is now Old Cairo). The Arabs capture it after a siege and establish their own garrison town just to the east, calling it Al Fustat.

The army then moves on to Alexandria, but here the defences are sufficient to keep them at bay for fourteen months. At the end of that time a surprising treaty is signed. The Greeks of Alexandria agree to leave peacefully; the Arabs give them a year in which to do so. In the autumn of 642, the handover duly occurs. One of the richest of Byzantine provinces has been lost to the Arabs without a fight.

From AD 843 icons recover their special position in Greek Orthodox Christianity, never again to lose it. The screen between the nave and the altar sanctuary in an Orthodox church is dedicated to the display of holy images - as its name iconostasis specifically states.

As other regions are converted to the Greek religion, in the Balkans and in Russia, the veneration of images spreads. Indeed to many people nowadays, after a millennium of the rich tradition of Russian Orthodox Christianity, the word 'icon' suggests first and foremost a Russian religious painting. And Russian icons, still being painted today, preserve much of the ancient Byzantine style.Byzantine revival: 10th century AD

During the 10th century the fortunes of Byzantium undergo a remarkable revival. Control is re-established over much of the Balkans when the Slavs are brought within the empire - first by their conversion to Greek Orthodox Christianity, then by treaties and alliances. Beyond the Danube the Russians also are converted to the faith, and are from time to time kept friendly by intermarriage with the imperial family in Constantinople.

At the same period Byzantine armies recover Anatolia, Syria and northern Mesopotamia - extending the imperial frontiers in a manner unprecedented since the eruption of Islam in the 7th century.

Even in Italy the Byzantine territory is enlarged in the south, where eviction of the Arabs brings the entire coastline of heel and toe (Apulia and Calabria) back under imperial control. Sicily at the same period is lost to the Arabs, in a prolonged struggle from the fall of Palermo in 831 to the loss of the last Byzantine stronghold in 965. But overall, at the time of the first Christian millennium, the prospects for the Byzantine empire seem brighter than for many years.

They are to be darkened again in the next century by the emergence of a new enemy on each flank - the Normans in the west, the Seljuk Turks in the east.

Byzantines and Turks: AD 1064-1071

In 1064 the Seljuk Turks, under their sultan Alp Arslan, invade Armenia - for many centuries a disputed frontier region between the Byzantine empire and neighbours to the east. Alp Arslan follows his success here with an attack on Georgia, in 1068. These acts of aggression prompt a response from the Byzantine emperor, Romanus IV Diogenes.

The armies meet in 1071 at Manzikert, near Lake Van. The battle, a resounding victory for the Seljuks, is a turning point in the story of the Byzantine empire. Within a few years there are Turkish tribes in many parts of Anatolia. Some of them are bitter enemies of the Seljuks, but the Seljuks are now the main power in this borderland between Islam and Christianity.

Emotive appeals: AD 1095-1096

In March 1095 the pope, Urban II, is holding a council of his bishops at Piacenza. It is attended by ambassadors from Constantinople. When the pope allows them to address the assembly, they make a passionate appeal for Christian soldiers to come and help the Byzantine emperor, Alexios I, in his struggles against the Turks. Everyone is impressed.

This seems to have been a seminal moment in inspiring the pope with an ambitious new idea. In November of the same year, at another council (this time at Clermont), Urban takes the issue a crucial step further. Word is spread that on November 27 he will make a great announcement. A platform is set up in a field outside the city gate. A large crowd assembles. The pope rises to address them.

He describes a pitiful state of affairs in the holiest places of Christendom, now in the hands of the Turks. Pilgrims are persecuted and even prevented from reaching the shrines. He urges Christians, rich and poor alike, to march east to recover Jerusalem. He contrasts the poverty and squabbling of life in Europe with an image of a promised land of prosperity and peace. He even offers a new inducement - a plenary indulgence to all who take part. (An indulgence saves the sinner some of the pain of Purgatory, with a plenary one promising greater remission.)

Crusaders should be ready, says the pope, to leave their homes in the late summer of 1096 (after the harvest is in). They should make their way to Constantinople, where a Christian army will assemble.

Constantinople and western Christians: AD 1097-1099

By April 1097 the various crusading groups are ready to advance together from Constantinople. They are accompanied at this stage by a Byzantine army, for the first task is to clear a route through Anatolia - recently seized from the Byzantines by the Seljuk Turks.

The immediate target, close to hand, is the Seljuk capital in the heavily fortified Byzantine town of Nicaea. After a siege it is taken, in June, and restored to the Byzantine emperor. This is virtually the last act of cooperation between the crusading armies of western Christians and the Greek emperor in Constantinople.

The first crusade recovers northwest Anatolia for the Byzantine empire, but the rest remains in Turkish hands. During the next century troubles multiply for Constantinople, particularly in its relations with western Europeans. The Normans of south Italy and Sicily, profoundly hostile to eastern Christianity, frequently raid the shores and islands of Greece. Antioch, beyond Anatolia, is also in Norman hands - after the leaders of the first crusade betray their agreement with the Byzantine emperor, allotting this ancient Greek city to the Norman Bohemund as a hereditary principality.

But there are even more intense hostilities at closer quarters, among merchants competing bitterly for trade in Constantinople.

Venice and Constantinople: AD 1082-1201

During the 12th century Venetian merchants make excellent use of the exclusive trading privilege granted them in the Byzantine empire, in 1082, for their help against the Normans. But their wealth and arrogance provoke profound hostility in Constantinople.

In an attempt to curb them, the emperor makes trading agreements with Genoa in 1169 and with Pisa in 1170, following this in 1171 with the confiscation of the goods of every Venetian merchant in the empire. In 1182 the people of Constantinople take matters into their own hands with a massacre of the Latins (or Roman Catholics) living in the city.

Dynastic conflicts in the last years of the 12th century compound the troubles of the Byzantine empire, and accidentally play into the hands of Venice. In 1195 the emperor Isaac II is deposed and blinded by his brother. Isaac's son, Alexius, is imprisoned. In 1201 he escapes and makes his way to western Europe to seek assistance in the recovery of his throne.

In the same year arrangements are being made in Europe for yet another crusade, the fourth, to the Middle East. This time it is proposed that the crusaders depart in a great fleet from Venice. The Venetians, masters of secret diplomacy, suddenly have all the necessary threads in their hands. They weave them into an intricate and profitable web of deceit.

The fourth crusade: AD 1202-1204

Inspired by the pope's preachers to set off for the east, a new wave of crusaders makes travel arrangements in Venice in 1201. Their immediate target is Egypt, now thought to be the most vulnerable part of Saladin's empire in the eastern Mediterranean.

Venice drives a hard bargain. The city will provide ships for 4500 knights and their horses, 9000 squires to serve them and 20,000 foot soldiers; food for a year for the entire expedition; and fifty galleys as an escort. For this the crusaders will pay 85,000 silver marks and will cede to Venice half of any lands they conquer. This is agreed, with a departure date planned for some time after June 1202.

Venetian diplomats immediately get in touch with the sultan in Egypt, with whom they have excellent trading agreements, to assure him secretly that Venice will not allow the crusading fleet to reach his shores. Behind the scenes the doge is also negotiating with agents of Alexius, son of the deposed emperor in Constantinople. It seems possible that the crusaders might be diverted to this rich and ancient city, where Venice by now has several grudges to settle.

Soon the hard facts of commerce are playing into Venetian hands. The crusading army is assembled in Venice by the summer of 1202. But it has nowhere near assembled the agreed sum of 85,000 silver marks.

The Venetians propose a compromise. They will accept deferred payment and yet honour their side of the bargain, if the crusading army will do them a small favour on the journey out to Egypt. Venice has for a while been disputing control of Dalmatia with the king of Hungary. The Hungarians have recently seized an important coastal city, Zara (now Zadar). It would be a fine thing if the crusaders would recover this city.

The crusaders sail from Venice on November 8 and arrive at Zara on November 10. They besiege the city for five days and pillage it for three. It is then decided that it is too late in the year to continue eastwards. They make a winter camp.

During the winter the Venetians agree terms with Alexius. If placed on the throne in Constantinople, he will pay Venice the sum owed by the crusaders. He will also provide funds and men to help the crusade on its way.

The proposal is put to the crusading army and with some reluctance is accepted. The fleet reaches Constantinople in June 1203. The crusaders break through the great chain protecting the harbour and breach the city walls in July. On August 1, in Santa Sophia, Alexius is crowned co-emperor - alongside his blind father. With the immediate purpose achieved, the crusade should be able to continue on its way. But now it is Alexius who cannot deliver his side of the bargain.

The sack of Constantinople: AD 1204

The crusaders camp outside Constantinople while Alexius, as emperor, tries to raise his debt to the Venetians by taxing the citizens and confiscating church property. For nine months growing resentment within the city is matched by increasing impatience outside. In April the Venetians persuade the crusaders to storm Constantinople and place a Latin emperor on the throne. For the second time they succeed in breaching the walls.

The doge of Venice and the leading crusaders instal themselves in the royal palace. The army is granted three days in which to pillage the city.

The Venetians, from their long links with Constantinople, can appreciate the treasures of Byzantium. They loot rather than destroy. St Mark's in Venice is graced today by many rich possessions brought back in 1204 - parts of the Pala d'Oro, the porphyry figures known as the tetrarchs, and above all the four great bronze horses.

The crusaders, mainly French and Flemish, are less refined in their tastes. They tend to smash what they find. They ride their horses into Santa Sophia, tear down its silken hangings, destroy the icons in the silver iconostasis. A prostitute, placed on the patriarch's throne, obligingly sings a bawdy song in Norman French.

Latin and Byzantine empires: AD 1204-1261

The seizure of Constantinople by the fourth crusade does wider damage than the physical destruction of the city. The Byzantine empire is fatally weakened by the crusaders who now grab fiefs for themselves in Greece and western Anatolia (following the example of the first crusaders, a century earlier, in Palestine and Syria).

A Latin empire is set up in Constantinople on the same feudal principle as the Latin kingdom of Jerusalem. One of the crusaders, Baldwin, Count of Flanders and Hainaut, is elected emperor. On 16 May 1204 he is crowned in Santa Sophia. Later in the year he distributes lordships to his vassals.

The Byzantine court survives, in a much reduced state, in the ancient city of Nicaea. From this base, over the next three generations, Byzantine emperors gradually push their Latin opponents westwards out of Anatolia. Eventually, in alliance with Venice's bitter enemy, Genoa, they succeed in 1261 in recovering Constantinople.

Byzantine emperors rule in Constantinople for almost another two centuries. But they are isolated, weak, and in the end helpless against encirclement by a new and powerful enemy - the Ottoman Turks.

The Ottoman Turks: 13th - 14th century AD

During the 13th century, when many Turkish emirates are being established in Anatolia, a petty chieftain by the name of Ertughrul wins control over a limited area around Sögüt, between Ankara and Constantinople. He is succeeded in about 1285 by his son Osman, whose name is a Turkish version of the Arabic Othman. Through Osman, seen later as founder of the dynasty, his people become known as the Ottoman Turks.

Most of the Turks of Anatolia live in a style in keeping with their origins, as fierce nomads of the steppes. Riding out to war is their everyday activity. But they are also keen Muslims. They see themselves as ghazi, an Arabic word for warrior but with religious connotations.

Turks setting out on a ghaza (armed raid) are indulging in an expedition of plunder but also in a jihad (holy war). It is a potent combination. The enfeebled Byzantine empire to the west of their territory - crippled, ironically, by the Christian fourth crusade - provides the Ottoman Turks with a natural target.

Progress is at first slow. The Ottoman horsemen lack the equipment to take fortified Byzantine towns. Instead they plunder the surrounding countryside, effectively strangling their victims into submission. Bursa, the first important Byzantine stronghold to the west, falls to them in 1326, the year of Osman's death.

After the fall of Bursa the Ottoman advance quickens. Nicaea yields in 1331 and Nicomedia in 1337. In that direction a narrow neck of land leads directly to Constantinople, but the Ottomans prefer a roundabout route. In 1354 they cross into Europe at the other end of the sea of Marmara, capturing Gallipoli. Eight years later Adrianople falls to them, severing the main route westwards from Constantinople.

A stranglehold is being applied to the Byzantine capital itself, but the Turks look first for plunder in an easier direction. They continue westwards into the Balkans, where their successes prompt the formation of the formidable Ottoman fighting force known as the Janissaries.

The Turks in the Balkans: AD 1389 - 140

A victory at Kosovo in 1389 brings Serbia under Ottoman control as a vassal state. The Ottoman sultan Murad I dies on the battlefield of Kosovo and is succeeded by his son Bayazid I, whose name Yildirim ('Thunderbolt') reflects his early military successes. The Slav kingdom of Bulgaria is fully occupied by 1393. In the following year Bayazid begins the long expected blockade of Constantinople. A Hungarian army marching as a crusade against the Turks is heavily defeated at Nicopolis in 1396. Meanwhile the sultan campaigns south into Greece. But then the Balkans and Constantinople are given a sudden reprieve.

Bayazid is confronted by a major threat in Anatolia - the arrival of Timur.

Retrenchment and recovery: AD 1402 - 1481
The Ottoman domain shrinks drastically after Bayazid's defeat and capture by Timur in 1402. The many small emirs of Turkey reassert their independence, as do the Balkan states. The three sons of Bayazid are left with only the family's central territories round the southern and western sides of the sea of Marmara. They fight each other in a civil war which is won by the youngest, Mehmed I, in 1413.

From this unpromising position, the son and grandson of Mehmed (Murad II and Mehmed II, whose combined reigns span nearly seventy years) achieve an astonishing recovery for the Ottoman state - posing an ever greater threat to the Byzantine empire.

Murad patiently reasserts control over much of western Anatolia, and makes equivalent headway in the Balkans. Serbia is brought back into the Ottoman fold (Murad marries a Serbian princess in 1433). Much of Bulgaria also is recovered. A strong counter-attack down the Danube in 1443 by an army of Hungarians and Poles is at first successful, until the Ottoman Turks win a decisive victory at Varna in 1444.

This steady process is continued by Murad's son, Mehmed II.

Mehmed II conquers Athens and almost the whole of the Greek peninsula in 1458-60. He then engages in a prolonged war with Venice, winning many valuable ports along the Adriatic coast. In 1463-4 he captures Bosnia where a large number of nobles convert to Islam, unlike neighbouring Serbia which remains largely Greek Orthodox - a distinction with resonance in more recent history. By the time of Mehmed's death, in 1481, Anatolia has also been recovered. Even regions north of the Black Sea are vassal states.

But the achievement which gives Mehmed his title of Fatih (Conqueror), and his secure place in history, has been his capture in 1453 of Constantinople.
Fall of Constantinople: AD 1453

A month after his twenty-first birthday, in April 1453, Mehmed II applies to Constantinople the stranglehold which has been a tacit threat for nearly a century, ever since the Ottoman capture of Adrianople (Edirne in its Turkish name) in 1362. He initiates a tight blockade of the city by both sea and land.

The inhabitants, as often before, place their faith in their immensely strong city walls. Only on the harbour side are these walls vulnerable, and the harbour (the long creek known as the Golden Horn) is protected by a great chain preventing enemy ships from entering. But the young sultan has an answer to that.

At dawn, one Sunday morning in May, the defenders on the walls are surprised to see Muslim ships in the harbour. During the night they have been dragged on wheeled carriages, on a temporary wooden roadway, over a 200-foot hill. Over the next few days cannon are moved into place, including one 19-ton bombard. At sunset on May 28 the attack begins. Every bell in the city rings the alarm. Santa Sophia is full of people praying and singing Kyrie Eleison (Lord, have mercy).

By dawn the Turks are in the city. The last Byzantine emperor, Constantine XI, has died in the fighting.

Mehmed, the sultan, goes straight to Santa Sophia to hear a proclamation from the pulpit - that there is no God but Allah, and Muhammad is his prophet. The great church, for many centuries the most magnificent in Christendom, now begins its career as a mosque. And Constantinople gradually acquires a new name; the urban area, widely referred to in everyday Greek as eis tin polin (in the city), becomes Istanbul.

The Ottoman army is allowed three days of pillage (a depressing convention of medieval warfare), but Mehmed keeps it under tolerable control. He has acquired a capital for his empire. He intends to preserve and improve it.

In an honourable Muslim tradition, he plans a multicultural and tolerant city. The population is much reduced, after decades of fear and uncertainty, so Mehmed brings Greeks from the Aegean (soon another part of his domain) to revive the place. The Greek Orthodox patriarch is left in charge of his flock. And when the Jews in Spain are expelled, in 1492, many of them come to Istanbul where it is official policy to welcome them.

Mehmed launches into a busy building programme, founding several mosques and beginning Topkapi Sarayi in 1462 as his own palace. Constantinople, transformed into Istanbul, is set to be a great imperial centre again. It has exchanged one empire for another, Byzantine for Ottoman.